Interposer Thermal Management for Stacked Semiconductor Chips

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Solution Overview

Problem

Stacked semiconductor chips face challenges in thermal management due to non-planar arrangements, leading to inadequate heat dissipation and limitations in power and size for lowermost dies, as conventional thermal interface materials struggle to establish effective thermal pathways.

Innovation Solution

The use of an interposer with a surface adapted to thermally contact a heat spreader, which includes an aperture for a second semiconductor chip, or covers a portion of the surface of a second semiconductor chip while having a footprint that does not extend beyond it, facilitating thermal conductivity and accommodating lateral expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If stacked dice arrangement is used to increase integration density, then device functionality is improved, but thermal contact between thermal interface material and lowermost chip deteriorates due to non-planarity

Engineering Contradiction:
Improveintegration densityVSAvoidthermal contact
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent introduces an interposer as an intermediary component between the lowermost chip and the thermal interface material. This interposer provides a planar mounting surface that ensures reliable thermal contact while accommodating the stacked dice arrangement above, thus resolving the contradiction between integration density and thermal contact reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent adds a vertical dimension by introducing the interposer layer beneath the stacked dice. This dimensional addition creates a planar interface at a different vertical level, allowing thermal contact to be maintained without compromising the stacked arrangement's integration density.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If interposer is introduced to improve thermal contact, then thermal management is improved, but device complexity increases

Engineering Contradiction:
Improvethermal contactVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The interposer serves multiple functions simultaneously: it provides a planar mounting surface for thermal contact, supports the stacked dice arrangement, and facilitates heat dissipation. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while improving thermal contact.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of manufacture

If conventional thermal interface material is used, then ease of manufacture is maintained, but thermal conductivity to lowermost chip is insufficient

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidheat dissipation efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The interposer acts as a mediator that enables conventional thermal interface materials to achieve effective thermal contact with the lowermost chip. By providing a planar surface, the interposer allows standard thermal interface materials to function effectively, maintaining ease of manufacture while improving heat dissipation efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enhances thermal management by establishing a conductive pathway from lower-level semiconductor chips to a heat spreader, improving heat dissipation and accommodating chip warpage, while allowing for flexible electrical routing and efficient thermal interface material application.

Implementation Method 1

The interposer includes a first surface seated on the first semiconductor chip and a second surface adapted to thermally contact a heat spreader

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS9385055B2Stacked semiconductor chips with thermal management
Publication Date: 2016.07.05 ATI TECHNOLOGIES ULC

AI summary

A method of assembling a semiconductor chip device is provided that includes placing an interposer on a first semiconductor chip. The interposer includes a first surface seated on the first semiconductor chip and a second surface adapted to thermally contact a heat spreader. The second surface includes a first aperture. A second semiconductor chip is placed in the first aperture.